A vertebrate homolog of the actin-bundling protein fascin

Abstract

Sea urchin fascin and the Drosophila singed gene product form a unique class of actin cross-linking proteins involved in the bundling of filamentous actin by an as yet unknown mechanism. From a Xenopus laevis intermediate pituitary cDNA library we have isolated a cDNA encoding a 53-kDa protein that shares approximately 36% amino acid sequence identity with both fascin and the singed gene product, and thus likely represents a vertebrate homolog of these actin-bundling proteins. RNase-protection experiments revealed that in Xenopus the gene is expressed in a wide variety of tissues but with the highest levels of expression in oocytes and testis. This raises the possibility that fascin has a role in microfilament dynamics associated with the formation and/or fertilization of vertebrate germ cells.